What Is Bronchitis?
2. Etiology
The commonest cause of acute bronchitis is due to infection from respiratory viruses. In chronic bronchitis, the predominant cause is due to cigarette smoking. The commonest viruses that can cause bronchitis include respiratory syncytial virus, coronavirus, parainfluenza, influenza A, and influenza B.
Other infectious pathogens that can be implicated are Streptococcus pneumoniae, Mycoplasma species, Moraxella catarrhalis, and Hemophilus influenzae. Bordetella pertussis is also increasingly reported. In chronic bronchitis, 85% to 90% of cases are thought to be due to cigarette smoking as this impairs the movement of cilia, inhibits alveolar macrophage function, and causes hyperplasia of mucus glands. Increasing air pollution has also been associated with increased respiratory health issues.
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